Adding new usable items (bow and bomb) and tricky puzzles that can be solved with them.

And new musics, sound fx, UI tweaks and general polish.

In terms of pricing, we don't know yet as we have to talk to Valve about it first, but it will be in line with your usual Steam indie game.

And finally, the release date is still planned for March 2013. When in March is again up to our discussions with Valve as we would like to have a single release date on all platforms if possible (most likely second half of March).